Hoval HomeVent®: Product efficiently put into series
23 July 2019
For the HomeVent® application from Hoval, the previously used connection housing system should be re-engineered. Learn how Prototech was able to improve the product within just a few optimization loops. And how AM in combination with vacuum casting can significantly minimize risks and costs.
Re-Engineering HomeVent® System
Fresh air awakens the spirit of life and activates the immune system. Particles susceptible to diseases such as viruses, bacteria, or molds must be minimized - a challenge for today's new buildings, which are more or less "airtight."
Hoval AG has developed a home ventilation system that optimally directs and distributes the filtered outside air to the inside, completely draught-free. Noise, dust and dirt particles remain outside, while odors and moisture are released to the outside in a controlled manner. The latest generation of the air diffuser has undergone a fundamental overhaul to improve assembly and installation.
To meet the product requirements of the individual components, it was necessary to validate the design solutions planned by Hoval in practical field tests. These were carried out in close cooperation with Prototech FL AG.
The field test series implementation comprised eight different development components, which were to be brought to series maturity in a few optimization loops. Furthermore, the approach of combining AM with vacuum casting for early validation of series parts is discussed in this showcase.
For the HomeVent® application, the previously used connection housing system was completely re-engineered. In order to achieve even greater assembly and installation safety, new design approaches were adopted in the construction system - remaining nails within the cast concrete sealing were to be avoided as a matter of principle.
In addition to the practicability on the construction site, important questions (uncertainties) concerned the functional design of the break-outs (especially the nails), the adjustability of the 2-component grid supports and the necessary frictional locking.
Choosing the right method
In an initial requirement evaluation, the vacuum casting process was decided upon, which is suitable for such a pilot and minimal series for the following reasons:
- best repeatability
- fast - also revised component geometries available within a few days
- 2K components with adjustable Shore hardness (25-95 Shore A)
- high flexibility, even inserts of any kind can be cast in a form-fit manner
- dozens of available materials (UL94, FAR 25, FDA approved, UV resistant),
- temperature resistant up to 120°C, etc.)
- Materials can be colored through in contrast to 3D printing (all RAL/NTSC color shades)
In comparison to the "linear" price scaling of AM, performance ratios of 40-80 components per silicone mold enable a high cost-benefit factor for prototype series, especially for complex or voluminous components with an edge length of up to 1.20m.
The next steps
In cooperation with the Hoval development team, Prototech first discussed the first design, optimized it and produced it using the vacuum casting process described above. During the field trials, various design details were further adapted on the basis of empirical findings. The revised components were then cast within a few days by Prototech FL AG and re-tested by Hoval.
These revised components include, for example, the friction-locked connecting elements. The optimum thickness, number of ribs and Shore hardness were quickly determined by vacuum casting. The same procedure has proven itself in the optimisation of the locking hook of the clamping strip. The geometries of the snap lock and the tension strap fastener were adapted and simplified on the basis of the practical tests.
The function validation of the dismountable housing cover was unproblematic in contrast to the nail break-outs. The challenge was that the nails had to withstand the impact of the nails during assembly, but they had to break out reliably when the housing was removed. During the field trials, it was found that the original design did not adequately meet the requirements. With the subsequent design change, the functionality could be demonstrated without much loss of time.
The results speak for themselves
In summary, it can be said that thanks to the close cooperation between the Hoval development team and Prototech, the new product was significantly improved within a few optimization loops. The process lasted only a few weeks and ranged from the first concept drafts to series maturity and preliminary tests on a real construction site. This showcase impressively demonstrates how AM, in combination with other processes such as vacuum casting, can significantly minimize risks and thus time and costs in the late phases of a product development project.
What the customer says
"Fast, competent and reliable. The cooperation with Prototech has worked well right from the start. A quick grasp of the required functionality and the pro-active engineering support in additive matters helped to bring this project efficiently into series production." Thomas Merhar (Development Manager Hoval)
Indirect processes (vacuum casting, metal casting etc.)